Nutrition Exam 3

(High) Blood Glucose Regulation - What are the three steps?

1. Insulin secretion: when blood glucose levels increase after a meal, the pancreas secrets the hormone insulin from the beta cells into the bloodstream

2. Cellular uptake: Insulin travels to the tissues. there it stimulates glucose transporters within cells to travel to the cell membrane, where they facilitate glucose transport into the cell to be used for energy

3. Glucose storage: Insulin also stimulates the storage of glucose in body tissues. Glucose is stored as glycogen in the liver and muscles (glycogenesis), and is stored as triglycerides in adipose tissues (lipogenesis)

(Low) Blood Glucose Regulation - What are the three steps?

1. Glucagon secretion: when blood glucose levels are low, the pancreas secrets the hormone glucagon from the alpha cells into the bloodstream

2. Glycogenolysis: Glucagon stimulates the liver to convert glycogen into glucose, which is released into the blood and transported to the cells for energy

3. Gluconeogenesis: Glucagon also assists in the breakdown of proteins and the uptake of amino acids by the liver, which creates glucose form amino acids

What hormones are involved in high blood glucose regulation and where are they made (which cells make them)?

Insulin - the pancreas secretes the hormone insulin from the beta cells into the bloodstream (after meal blood glucose levels increase)

Why is insulin secreted and where do they act/what do they do? (High Blood Glucose Regulation)

Insulin is secreted to lower blood sugar levels by promoting glucose uptake into tissues. Insulin travels to the tissues where it stimulates glucose transporters within cells to eventually facilitate glucose transport into the cell to be used for energy. Also stimulates storage of glucose in body tissues.

What hormones are involved in low blood glucose regulation and where are they made (which cells make them)?

Glucagon - pancreas secretes glucagon from the alpha cells into the bloodstream (when blood glucose levels are low)

Why is glucagon secreted and where do they act/what do they do? (Low Blood Glucose Regulation)

Glucagon is secreted to raise blood sugar levels (acts against insulin). Glucagon stimulates the liver to convert stored glycogen into glucose, which is released into the blood and transported to the cells for energy. (glycogenolysis) Also assists in breakdown of proteins and uptake of amino acids by liver. (Gluconeogenesis)

What is the problem with fructose? (fructose vs. glucose)

Glucose causes insulin release from the pancreas but fructose does not! (insulin release inhibits food intake)

Fructose absorbed in small intestine, cannot be used by the brain or communicate that you are full, you will eat.drink more if high in fructose.

What is glycemic index?

The potential for foods to increase blood glucose levels

—>high glycemic index = spike in blood glucose (also spike in insulin)

What is glycemic load?

Glycemic load = (number of grams of carbohydrates of serving X the food’s glycemic index) / 100

—tool that measures impact of food on blood sugar levels by combining quality of carbs (glycemic index) with the quantity (serving size)

What is the difference between glycemic index and glycemic load?

Glycemic index measures speed at which food raises blood sugar while Glycemic load accounts for both the speed (GI) and the portion size

—> even foods with high GI may have low GL due to low total carbs per serving

—>GI rank carbs on how fast carbs raise ; GL calculate the actual impact

Calculate glycemic load if given glycemic index and amount of carbs

Glycemic load = (number of grams of carbohydrates of serving X the food’s glycemic index) / 100

—> multiply GI by the amount of carbs in a serving, then divide by 100

Why does Type 1 Diabetes happen?

Immune system mistakenly attacks and destroys insulin-producing beta cells in the pancreas.

Which cells are destroyed/damaged and why in Type 1 Diabetes?

Beta cells of pancreas are damaged or destroyed.

How do we treat Type 1 Diabetes?

Take insulin - injections, pump, etc to manage blood sugar levels as the body no longer produces its own

Why does Type 2 Diabetes happen?

Cells fail to respond properly to insulin, forcing the pancreas to overproduce it until it can no longer meet the body’s needs, causing blood sugar to rise

—> genetic factors and lifestyle factors (obesity and physical inactivity lead to insulin resistance and pancreatic dysfunction)

Which cells are destroyed/damaged and why in Type 2 Diabetes?

None BUT cells fail to respond to insulin adequately so progressively higher amounts of insulin must be produced by the pancreas to stimulate cells to uptake glucose (thus high glucose levels in bloodstream)

How do we treat Type 2 Diabetes?

Insulin resistance; focus on lowering blood sugar through lifestyle changes (diet, exercise, weight loss) and medications

What are normal fasting blood glucose levels? A1C percents?

Normal fasting levels: 99 or below

A1C percents: About 5

What are blood glucose levels? What are A1C levels that are considered diabetic?

Blood glucose levels measure the among of sugar (glucose) in your bood, which provides energy to the body’s cells.

A1C levels considered diabetic: 6.5% or above

Fasting plasma glucose 126 or above, oral glucose 200 or above (diabetic)

Type 1 Diabetes Symptoms

Increased or frequent urination, excessive thirst, constant hunger, unexplained weight loss, extreme fatigue, blurred vision

Type 2 Diabetes Symptoms

Any of the type 1 signs and symptoms, greater frequency of infections, sudden vision changes, slow healing of wounds or sores, tingling or numbness in the hands or feet, very dry skin

What are fats?

Subset of lipids

What are characteristics of fats?

insoluble in water, make up cell membrane, necessary as energy source to the body, most energy gained from this macronutrient, involved in MANY normal cellular processes, dietary lipids (fat and oil)

What are general characteristics of triglycerides?

most common food-based fat, glycerol backbone, 3 fatty acids attached to glycerol, at one end of fatty acid is a carboxyl group (COOH) acid, methyl group (CH3) at the other end called omega end

How are triglycerides classified?

Classified by carbon chain length, level of saturation (how many hydrogen attached to carbon), and shape

What are the differences between short, medium, and long chain fatty acids?

short-chain fatty acids = less than 6 carbons

medium-chain fatty acids = 6-12 carbons

long-chain fatty acids = 14 or more

—> if longer more effort to digest and absorb

What are saturated fats?

No double bonds between carbons (saturated with hydrogen)\

Solid at room temperature —> lard, butter

What are unsaturated fats?

Have double bonds: 2 types - liquid at room temp

1. Monounsaturated fatty acids (MUFA) : one double bond - olive oil, canola oil

2. Polyunsaturated fatty acids (PUFA) : more than one double bond - corn oil, sesame oil

Animal fats

saturated

Plant fats

unsaturated

How does saturated/unsaturated influence shape and appearance?

Long-chain saturated fatty acids stack well together to make solid forms at room temperature.

Monounsaturated and polyunsaturated fatty acids do not stack well together because they are bent. Liquid at room temp

What is level of saturation?

Hydrogen atoms attached to carbon

What is the shape of saturated fats?

straight and pack tightly together

What is the shape of unsaturated fats?

bends due to double bonds making them less compact

Most saturated fat items

butter, whole milk, beef

Most unsaturated fatty acids

oils

What does saturation level affect?

Affects how easily fats are digested and absorbed by the body

What are saturated fats associated with?

Higher health risks; unsaturated fats are generally healthier

What are trans fats?

Trans fats make unsaturated fats look and behave more like saturated fats

How are trans fats made?

Artificially saturated through hydrogenation—blasting oils with hydrogen and rearranging the double bonds; THEY ARE BAD FOR YOU

What are essential fatty acids?

Omega fats

Why are omega fats essential?

They are precursors of eicosanoids (acting like hormones and rapidly metabolized)

They regular cell function, and contain a linoleic acid which is a cell membrane structure required for lipoproteins (lowers LDL)

How are omega fatty acids classified/named?

Omega-6 and Omega-3

What is the name of Omega-3 based on?

Name based on the position of double bonds relative to the omega end (methyl group at end of fatty acid chain)

What are the sources of Omega fatty acids in the diet?

Omega 3: salmon, tuna, algae

Omega 6: oils

Why are omega fatty acids beneficial?

Reduce inflammation, supports cognitive function (DHA - Mood regulation)

What are characteristics of phospholipids?

Two fatty acids attached to glycerol —> attached to phosphate

What are phospholipids and why are they important?

They make up the phospholipid bilayer of cells

What are characteristics of sterols?

Lipids with multiple-ring structure, found in plant and animal foods and produced in the body; most common in cholesterol

What are sterols and why are they important?

Natural, plant-based compounds structurally similar to cholesterol that serve as essential components of plant cell membranes

Why do we need fats?

Fats provide energy (9kcal/g) and sustain us at rest (30-70% of energy needs) and require oxygen to break down

Stored for later use during exercise when we haven’t eaten or while sleeping

How do fats fuel physical activity over time?

We use quick fuel stores first but hormones dictate which fuel source to use: Adrenaline mobilizes stored fat for energy, Insulin blocks fat breakdown, so it remains low during exercise

The longer you exercise the more fat you burn

The more fit you are, the more oxygen your body can use to burn more fat

What else do fats do that is not related to fuel?

Enable transport of fat-soluble vitamins (ADEK)

Maintain cell function

Provide protection for organs and insulation

Make food taste good!

How is fat digested and absorbed by the body?

Occurs primarily in the small intestine; bile emulsifies fats and pancreatic lipase breaks them into free fatty acids and monoglycerides —> converted into chylomicrons

What lipoprotein has the most protein?

HDL - High density lipoprotein

What is the lipoprotein VLDL?

Transports triglycerides into the bloodstream to be used by cells as needed or stored as fat

What is the lipoprotein LDL?

made from VLDLs minus triglyceride, rich in cholesterol and is taken up by cells around the body (if not removed can be BAD CHOLESTEROL)

—> plaque build on artery walls but exercise and healthy diet can lower this

What is the lipoprotein HDL?

Produced in the liver and scavenge cholesterol around the body to be eliminated

What is good cholesterol? Where are they made?

HDL - made by the liver (mostly), intestines, and blood which is transported around the body

What is the recommended levels for total cholesterol level?

Less than 200 mg/dL

What is the recommended levels for LDL bad cholesterol level?

Less than 100 mg/dL

What is the recommended level for HDL good cholesterol level?

60 mg/dL and higher

What does fat-free food label mean?

Less than 0.5g of fat

What does low fat food label mean?

3g or less

What does reduced fat food label mean?

25% less fat compared to the standard serving

What does light food label mean?

1/3 fewer calories or 50% less fat compared to standard serving

What is the recommendations (AMDR) for athletes?

20-25% Fat

55-60% Carbs

12-15% Protein

If trying to lose weight, what is the recommendation? What is counterproductive?

Reducing fat and calories causes more harm than good; keeping fat % the same for more success

Omega 6 vs Omega 3 FIGHT: What’s difference (acids)

Omega 6 = Linolenic acid

Omega 3 = Alpha-linolenic acid

What are proteins?

Large complex molecules found in cells and perform many critical functions

Cellular processes require proteins, so they are necessary for normal cell structure and function

What are amino acids?

Amino acids are building blocks

What do proteins contain?

Nitrogen - nitrogen is in the amine group of amino acids

What makes a protein (what is unique about the structure)?

20 different amino acids, each unique with side chain (10,000-50,000)

What are the essential amino acids?

9 essential amino acids

Lysine, Methionine, Tryptophan, Valine, Phenylalanine, Isoleucine, Leucine, Threonine, Histidine (WHATEVER HAS AN A IS WRONG - exam)

What is the consequences of not getting enough essential amino acids in the diet?

If we don’t have all of these, we fail to make the proteins that are composed of the amino acid

can cause: immune dysfunction, infertility, advanced aging, death

What are non essential amino acids and how are they made?

The amine group coming from essential amino acid make them nonessential amino acid; made through transamination

What does it mean to say a non essential amino acid is conditionally essential?

A typically nonessential amino acid that is essential due to the body’s inability to break down an essential amino acid needed to make it

What are peptides?

Amine group of one amino acid binds to the acid group of another and water is released

What is a dipeptide?

2 amino acids

What is a tripeptide?

3 amino acids

What is an oligopeptide?

4-9 amino acids

What is a polypeptide chain?

10 or more amino acids

What is the significance of protein organization?

The shape of proteins contained within a cell dictate the shape of the cell and that dictates function

How do you alter proteins and what is that impact?

If you change the protein, then you can change the function; can be good or bad

pH, Heat, Alcohol

What is the consequence of not getting enough amino acids in the diet?

If you do not have enough amino acids to make a protein (complete protein), it isn’t made adequately (incomplete protein); if you don’t consume enough energy, you won’t be able to make protein = you are busy breaking them down

What are mutual supplementation examples (protein unit)?

Legumes and grains

Vegetables and Legumes

Nuts and seeds and Legumes

What foods contain all 9 essential amino acids (complete proteins)?

Beef, poultry, fish, eggs, dairy, soy, quinoa, buckwheat, hemp seed

What is the importance of proteins in the body?

Transport things across the cell membrane in the body; enzymes, hormones, cell growth, repair, maintenance, NT’s, antibodies, carry oxygen, clotting factors

How are proteins processed by the body?

Digestion of dietary proteins into single amino acids occurs primarily in the stomach and small intestine; the single amino acids are then transported to the liver where they may be converted to glucose or fat, used for energy to build new proteins, or transported to cells as needed

What is important to break down protein?

Pepsin

What is a negative nitrogen balance?

Results from starvation, consumption or very low energy diets, severe illness, infections, serious burns or injuries

What is a positive nitrogen balance?

Needed for periods of growth, pregnancy, recovery from illness, or protein deficiency

How is nitrogen balance measured?

Your urine and feces are collected to measure how much nitrogen you excrete (consumption vs excretion)

How much protein do you need/how do you calculate it?

Body weight in kgs (body weight/2.2) X 0.8-1.7 (dependent on protein needs based off activity)

What is the RDA (recommended dietary allowance) for protein?

10-35% ; most Americans meet or exceed RDA for protein ; athletes, elderly, pregnant women, and children are usually on the high side of the range

What are sources of protein other than meat?

Dairy products, eggs, legumes including soy, whole grains → Ancient grains: quinoa, amaranth, millet, and sorghum, nuts → high in protein and reduces risk of cardiovascular disease, providing unsaturated fats

What are examples of bad diets?

Macrobiotic diet: vegan type diet; becomes progressively more strict until almost all foods are eliminated; at the extreme, only brown rice, and small amounts of water or herbal tea

Fruititarian: only raw or dried fruit, seeds, nuts, honey, and vegetable oil

What are examples of good diets?

Pescovegetarian: only animal source is fish

Lacto-ovo-vegetarians: can eat eggs, vegetables, grains, nuts, fruits, legumes, dairy products

Lacto-vegetarian: excludes eggs but same as ovo